Maybe it is differ from hardware manufacture, my I need a fresh cache, I use kext wizard to generate a a new cache, other than that event I change in clover it is not work.

my 7850 and 7870 I used the same clover-graphics, one connect to HDMI, one port connect to DVI either one would work, the 7870 one port to HDMI other with mini display port to HDMI adapter-------- both card go straight to desktop w/o sleep trick